An improved method of TEF considering the saturation of inverter under VSG strategy

[摘要] In order to reduce influence of the total inertia of the system on the system stability, the virtual synchronous generator(VSG) technology is becoming a research hotspot for the penetration of distributed power supply with high permeability. Due to the existence of the current limiter in the inverter, the transient energy function which is constructed by first integral (TEF) derivative is not monotonous. It may make using TEF method to obtain the critical clearing time and system stability error. This paper proposes an improved TEF method using the tangent function to replace the saturation one. Firstly, the relationship between the virtual power angle and the power angle of the traditional system is analyzed after the improvement of the inverter current saturation link. Then, the first integral method is used to construct the TEF with improved saturation. Finally, it simulates to a single machine infinite bus system and IEEE three-machine-nine-bus system by MATLAB/Simulink, and the results show that the improved TEF is proposed, it can effectively evaluate the VSG strategy and the transient stability of AC system inverter current limiting.

[发布机构] Power Grid Technology Department, State Grid Jiangsu Electric Power Company Research Institute, Nanjing; 211100, China^1;School of Automation, Nanjing University of Science and Technology, Nanjing; 210094, China^2

[效力级别] 电工学

[关键词] Critical clearing time;Distributed power supplies;First integral method;High permeability;Single machine infinite bus system;Tangent functions;Traditional systems;Transient energy functions